Fluid fuel burner assembly



5 Sheets-Sheet 2 J. W. LANNERT ET AL FLUID FUEL BURNER ASSEMBLY July 12,1966 Filed April 29, 1960 whim t 0": I l ldul a x M c ..a F \4 1| J. W.LANNERT ET AL FLUID FUEL BURNER ASSEMBLY July 12, 1966 Filed April 29,1960 5 Sheets-Sheet 5 Wr/klb July 12, 1966 1 w, LANNERT ET AL 43,260,300

FLUID FUEL BURNER ASSEMBLY Filed April 29, 1960 5 Sheets-Sheet 4 I i&2:.-2

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I I 2 i f w J55 14-0 .13 171 5 I ,Jjo '5 J14- j'jz 12 \W 149 fljforneysL July 12, 1966 Filed April 29, 1960 J. W. LANNERT ET AL FLUIDVFUELBURNER ASSEMBLY 5 Sheets-Sheet 5 Ema: (Ill 177 flbward EBre/i "7J5 w gzmUnited States Patent 3,260,300 FLUID FUEL BURNER ASSEMBLY James W.Lannert and Howard E. Brehm, J12, St. Joseph,

Mich., assignors to Whirlpool Corporation, a corporation of DelawareFiled Apr. 29, 1960, Ser. No. 25,793 3 Claims. (Cl. 158116) Thisinvention relates to a flui-d fuel burner assembly of the type used, forexample, in a gas stove.

One of the features of this invention is to provide an improved fluidfuel burner assembly preferably of small horizontal cross sectionaldimensions in which the flame is projected radially with respect to thecentral axis of the assembly to extend around the assembly with theflame being substantially in sheet form and preferably having a layer ofsecondary air above the flame which would place it between the main bodyof the flame and the article such as a pot or pan being heated.

1 A further feature of the invention is to provide an improved assemblyin which there is a high turndown ratio such as a maximum ofapproximately 36: 1.

Another feature of the invention is to provide an improved fluid fuelburner assembly having means for providing a fuel-primary air mixturefor ignition to provide a sheet of flame and means for providing anoverlying body of secondary air in which the secondary air may besupplied by a blower and wherein the secondary air at its exit from theassembly will be at a relatively high velocity.

Another feature of the invention is to provide an improved fluid fuelburner assembly in which an internal passage is provided to supply afuel-air mixture for initial ignition with this passage being ventedthrough one or more side openings to the exterior of the assembly forignition by a suitable device such as a pilot flame so that the flame ofthis initially ignited mixture is carried upwardly to the emerging mainfuel-air mixture from the burner for ignition thereof, the upper end ofthe initial ignition fuel-air mixture passage preferably being vented toatmosphere in order to prevent excessive pressure buildup within thispassage when the gas and primary air pressure is increased within theburner.

Yet another feature of the invention is to provide a fluid fuel burnerassembly in which improved means are provided for sealing the assemblyto a top plate such as a range top plate whereby cleanability is vastlyimproved.

A further feature of the invention is to provide an improved burnerassembly located adjacent means providing a pilot flame together with ashield surrounding the upper portion of the assembly and enclosing thepilot flame.

A further feature is to provide a powered secondary air burner havingparts common to an atmospheric burner in which the secondary air forcombustion is not powered.

Other features and advantages of the invention will be apparent from thefollowing description of certain embodiments thereof taken inconjunction with the accompanying drawings. Of the drawings:

FIGURE 1 is a sectional elevational view partially broken away showingone embodiment of a fluid fuel burner assembly arranged in conjunctionwith a range top and associated structure.

FIGURE 2 is a plan view of the burner assembly of FIGURE 1.

FIGURE 3 is a vertical sectional view taken substantially along line 33of FIGURE 1.

FIGURE 4 is a horizontal sectional view taken substantially along line44 of FIGURE 3.

FIGURE 5 is a fragmentary sectional view showing a second embodiment ofthe invention.

FIGURE 6 is a fragmentary vertical sectional view similar to FIGURE 3but showing a third embodiment of the invention.

FIGURE 7 is a view similar to FIGURE 1 but showing a fourth embodimentof the invention.

FIGURE 8 is a view similar to FIGURE 1 but showing a fifth embodiment ofthe invention.

FIGURE 9 is a view similar to FIGURE 3 showing a sixth embodiment of theinvention.

FIGURE 10 is a sectional view taken substantially along line 1010 ofFIGURE 9.

FIGURE 11 is a sectional view taken substantially along line 1111 ofFIGURE 10.

FIGURE 12 is a fragmentary sectional view taken sub stantially alongline 12-12 of FIGURE 10.

FIGURE 13 is a view similar to FIGURE 9 but showing a seventh embodimentof the invention.

The fluid fuel burner assembly of this invention is particularly usefulin gas ranges and the like particularly at the top of the range. In theembodiment illustrated in FIGURES l-4 inclusive the range includes asheet metal range top 10 having a surface portion 11 of counter heightwith the main body portion 12 thereof lowered. Located in this range topare a plurality of burner assemblies 13 spaced in the customary mannerof which only one is shown for illustrative purposes. The burnerassembly 13 extends through an opening in the range top 10 formed by anupturned annular flange 14 with the burner assembly being sealed to thisflange and the adjacent portion of the top '10 by means of a resilientheat-resistant rubbery seal The fluid fuel burner assembly 13 comprisesa burner head or head unit 16 of generally cylindrical shape including acylindrical outer wall 17, a generally vertical wall 18 spaced inwardlythereof and a central tube 19. The wall.=18 is of a heavier constructionthan the outer wall 17 as it serves as a principal support of the burnerhead unit.

The top of the wall 18 projects outwardly and upwardly as indicated at20 to overhang partially an upwardly and outwardly extending annularflange 21 on the outer wall 17. The space between the wall flange 20 andthe wall flange 21 provides an outlet 22 extending somewhat less than360 around the burner body.

The top portion of .the burner head unit 16 is provided with a pluralityof exit ports 23. These ports may be formed by drilling the top of thecylindrical wall 18 with the drilled ports having open tops as indicatedin FIG- URE 4 and are closed by an overlying plate 24.

The plate 24 is relatively heavy and is of generally short funnel shapewith a central portion 25 and an upwardly and outwardly extendingoverlying portion 26. The outer edge of this overlying portion 26 closesthe upper extremities of the drilled ports 23.

The left-hand side of the wall 18, as viewed in FIG- URE l, is recessedinwardly and includes an upper portion 27 and an inwardly sloped lowerportion 28. The space between the portions 27-28 and the adjacent outerwall portion 29 provides an initial ignition fuel-air mixture passage30. The outer extremity of the upper end of this passage 30 is definedby a wall portion 29a which is aligned with portion 29 and which isintegral with wall 18. The outer wall portions 29 and 29a are providedwith openings 31 and 31a extending vertically from adjacent the bottomof the burner head unit 16 to the plurality of drilled ports 23.

Attached to the lower end of the central portion 25 of the plate 24 is adepending tube 19 having its upper end attached to this portion 25.Extending across the central portion 25 of the plate 24 is a spider 33providing a plurality of circumferentially arranged openings. Mounted onthis spider by means of a post 34 is a top plate 35 having its outeredge substantially vertically aligned with the outer edges of th flange20 and the plate 24. The top plate 35 is spaced from the plate 24 toprovide an exit J opening 36 extending completely around the top of theburner assembly. In this embodiment wall 17, Wall 18, plate 24, spider33, post 34 and top plate 35 are all attached together to form theburner head or head unit. Tube 19 may also be attached to this unit, ifdesired, as may be hood 63, the function of which will be describedlater.

The burner unit 16 is positioned, when assembled, on a burner base 37having a top wall 33 with its inner edge spaced from tube 19 to providean opening 39 therearound and a cylindrical side wall 40. The upper Wall38 of burner base 37 is provided with a plurality of openings 42 whosefunction is to provide communication between passages 47 and 45. Theplurality of openings are positioned on a circle with th longitudinalaxis 43 passing through the center of this circle. Also provided in theupper wall 38 of burner base 37 is a single opening 41 that withadjacent holes 42 allows the primary fuel-air mixture to pass frompassage 47 into the initial ignition passage 3%. The center of the tube19 provides a passage 46 and the space between the tub 19 and the Wallwithin the base 37 provides the passage 47.

Connected to the bottom of the base 37 to communicate with the passage47 is a conduit pipe 48 for gas and primary air mixture.

The burner end of this pipe 48 is assembled in a sealed relationship toburner assembly 13. This is provided by having the inner end turnedoutwardly to provide an annular flange 49 which is held in a groove 50and which is sealed to the base 37 as by a resilient seal member 51.

A pipe 52 for air under superatmospheric pressure is provided on thebottom of the base 37 communicating with the chamber 53 that is providedwith a bottom wall 54 with this chamber opening upwardly into thepassage 46 in the interior of the tube 19. The inner end of the pipe 52is provided with an orifice 55 through which the air flows from the pipe52 into the chamber 53.

Extending around the wall 40 beneath the adjacent portion 12 of therange top 10 is a transverse supporting metal plate 56, The bottom ofthe resilient seal member 15 rests against the top of this plate 56.Extending through this plate 56, an outwardly extending potrion 57 ofthe seal member 15 and the range top 10 is a threaded pilot nozzle 58held in place by upper and lower clamping nuts 59. The bottom of thisnozzle 58 has attached thereto a fuel pipe 66 to provide gaseous fuel tothe interior of the nozzle 58. This fuel is emitted through an opening61 in the top of the nozzle 58 to provide a pilot flame 62 extendingtoward the vertical row of openings 31 in Wall 29 which serves to ignitethe fuel-air mixture as it passes through the openings 31 from theinitial ignition fuel-air passage 30. If desired, a single elongatedopening or a plurality of elongated openings may be provided instead ofthe plurality of circular openings 31 shown.

Attached to the outer wall 17 is a depending hood 63 having its bottomspaced from the range top flange 14. One side of this hood 63 extendsoutwardly to enclose the top end of the pilot nozzle 58 and is providedwith a sloping top 64 in which is located a relatively large opening 65adjacent the outer wall portion 23 containing the openings 31. As can beseen in FIGURE 1, the bottom of this hood 63 is spaced from the rangetop 119.

In operation, gas and primary air under pressure flow through the pipe48 and into the passage 47. The mixture then flows up through theopening 39 into the passage 44 and out the burning ports 23. This gasand primary air mixture also flows through opening 41 into the initialignition passage 34 and through the openings 42 into the passage 45 andout the gas relight outlet 22. In addition, secondary air under pressureis fed through the pipe 52, orifice 55 and chamber 53 into the passage46 and through the openings in the spider 33 to flow outwardly underpressure through the exit opening 36.

From the ignition openings 31 and 31a the primary air and gas mixtureflows to the exterior surface of the wall 4 portions 29 and 29a and isignited by the pilot flame 62 to carry the flame upwardly to the mainports 23 to ignite the primary air and gas mixture flowing therefrom,

As can be seen, the flame emerging from the main burner ports 23 isprojected outwardly at a slight upward angle all the way around theburner assembly. The top of this sheet of flame is contacted by anoutwardly projecting layer of secondary air flowing under pressure fromthe exit opening 36. Thus the sheetof secondary air is between the sheetof flame and the pot or vessel being heated. It is this sheet ofsecondary air which produces more uniform heat distribution, especiallyat low heat inputs, to thereby minimize hot spots in pans or utensilssometimes produced by conventional burners. A pot or vessel may besupported on a customary grate as illustrated at 66.

In this invention a blower may be used to provide the secondary air. Theburner of this invention permits an extremely high turndown ratio of itsmaximum to minimum inputs. Thus in some embodiments this turndown ratiohas been as much as 36:1 although satisfactory commercial ratios havebeen found to be from about 12:1 to 24:1. The burner of this inventionprovides extremely efiicient performance with a relatively small crosssectional area burner. Thus by providing the pressurized secondary airas described, there is no need for the usual aeration bowl and largeopen grate customarily used in burners for stoves. In addition, superiorcleanability is achieved and the burning unit is considerably moreattractive than the usual unit.

The design of the burner of this invention is such that the highturndown ratio is achieved both by providing for an increased maximuminput for fast heating operations without the danger of the flame beingpulled from the burner ports, and providing for a decreased minimuminput for simmering operations without localized hot spots.

The ports of a gas burner must be small enough so that the linearvelocity of the primary air-fuel mixture passing through the ports atthe lowest burner input is greater than the linear combustion rate ofthe mixture. This assures that flash back, which is the process of thecombustion moving toward the air-fuel mixture source, will not occur.However, as the input to the burner is increased, the linear velocity ofthe air-fuel mixture passing through the burner increases to the extentthat this linear velocity is considerably greater than the linearcombustion rate of the mixture and the flame is actually blown off ofthe burner.

On burners of this type, this condition makes it necessary to limit theupper input to the burner. The openings 42, passage 45, and outlet 22combine to overcome this high input limitation on the burner of thisinvention. The area of each opening 42 is made small enough so that whenthe burner is operated through its low input range only a negligibleamount of the fuel-air mixture passes through each opening 42 and thus avisible ring of flame will not be present at the continuous outlet 22.However, as the input to the burner is increased into the higher inputrange the pressure in passage 47 increases correspondingly and enoughair-fuel mixture passes through the openings 42 into the passage 45 andis ignited at 22 to form a visible continuous ring of flame directlybeneath the main burner ports 23. As the input is increased, the linearvelocity of the air-fuel mixture passing through the ports may becomegreat enough so that the flame is blown oil? of the burner. When thishappens, the flame retention or flame relight ring which is burning atcontinuous outlet 22 will continuously re-ignite the air-fuel mixturepassing through the burner ports 23. This flame retention or flamerelight ring therefore permits the increasing of the input to the burnerfor fast heating operations.

It is presently common practice on more expensive burners for low inputsto place a small simmer or low heat burner Within the normal burner.Even though this type of low heat burner has a small input, the area ofthe flame emitted is also very small and a hot spot will develop on theutensil directly above this small flame. This hot spot is of suchintensity that if the contents of the utensil, such as white sauce, arenot continually stirred, they will burn. However, the burner of thisinvention, with inputs comparable to the lowest inputs of the simmer orlow heat burner, by means of the powered blanket of secondary airpassing through continuous outlet 36 flattens the flame and spreads theheat of the flame at this low input into a large area such that no hotspots develop so that, for example, a white sauce in a utensil will notburn when left unattended over this type of burner. The effect of theblanket of powered secondary air at the minimum input of approximately500 B.t.u. per hour is so pronounced in its elimination of hot spotsthat a piece of paper can be placed of an inch above the flame comingfrom ports 23 without igniting. Of course this blanket of poweredsecondary air even at the maximum burner input acts to spread the flameover the entire area of the bottom of the utensil.

Although the dual type gas range top burners that use the center simmerburner for low inputs are capable of operating in the 500 B.t.u. perhour input range, the much more common single range top burner isusually limited to a minimum input of approximately 1000 B.t.u. per hourwhich is too high for some simmering operations.

When the burner is operated at a higher rate by increasing flow of gasand primary air there is no danger of the pilot flame that is located onthe exterior surfaces of the wall portions 29 and 29a adjacent theopenings 31 and 31a being blown off. This is prevented because the topof the pilot passage is vented through two of the main ports 23 by wayof passage 30a (FIGURE 4) in the illustrated embodiment, therebypreventing an excessive pressure build-up within the pilot passage. Inaddition, even at this high pressure when the burner is operating athigh capacity, flow through the pilot passage 30 is restricted by reasonof the relatively small flow passage openings 41 and 42.

If desired for economy reasons convection secondary air could be used.In this instance it would be necessary to remove the bottom wall 54 ofthe chamber 53, spider 33, post 34 and top plate 35 to permit secondaryair to flow by natural convection into the passage 46 and out the top oftube 19 where it is forced outwardly in all directions as it contactsthe bottom of the utensil.

In the embodiment of FIGURES 1-4, the flanges 20, 21 and 26 are slopedupwardly and outwardly. In the embodiment of FIGURE 5 the flange 67which corresponds to the flange 20 extends substantially horizontallybut has a downwardly and outwardly sloped bottom 68 while the flange 69which corresponds with the flange 21 is sloped outwardly and downwardly.With this construction the flame emerging from the outlet 70 is directedgenerally downwardly at the outer edge of this outlet. Under certainconditions, this downwardly directed configuration is more desirable forignition purposes because of the localized gas turbulence produced bythis construction.

In the embodiment shown in FIGURE 6 there is illustrated a manner inwhich a sensor control unit 71 may be positioned in the burner. As iswell known, sensor controls are used for thermostatic control of burnerflame depending upon the temperature of the vessel or pot being heated.In this embodiment the sensor body 72 extends upwardly through thebottom wall 54 into the passage 46 with the sensor body being spacedinwardly of the tube 19 to provide fluid flow therebetween. The bottomof the sensor is held in place by means of a plate 73 held in positionby bolts 74. Sealing gaskets 75 and 76 are employed in order to seal thespaces around the bottom of sensor control 71. The usual control wires77 are provided leading to operate the customary solenoid valve (notshown) in the gas supply line; The top of the sensor unit 71 includesthe usual spring loaded 6 sensor 78 which will be depressed against theurging of the spring 79 to the position shown in dotted lines when thesensor is in use.

In the embodiment shown in FIGURE 7 there is provided the primary airand gas supply passage 80, the pipe 81 leading to this passage, asecondary air passage 82 and a pipe 83 leading thereto, the secondaryair outlet 84, main burner ports 85 and flame relight ring outletopening 86. In this embodiment the pilot nozzle 87 and pilot flame 104are located beneath the range top 10 and the initial ignition passage 88extends downwardly beneath this range top. A shield 89 is provided abovethe pilot nozzle 87 in order to shield the pilot flame and preventoverheating of the range top 10 above the pilot. The range top aroundthe burner 90 of this embodiment is provided with an upwardly extendingflange 91 spaced outwardly thereof to provide an air passage 92. The topof this passage is enclosed by an outwardly spaced hood or shield 93with dependent sides 105 around which is spaced the lower supportingportion of grate 94. The opening 92 covered by the hood or shield 93except for a small pilot outlet opening 95 permits an additional supplyof secondary air to flow from under the range top 10, through theannular opening 92 downwardly and outwardly beneath the hood or shield93 and upwardly around this hood or shield 93 to the flame area. In thisembodiment the placing of the pilot beneath the range top removes itfrom sight and results in a controlled range top. The operation of thisembodiment is otherwise essentially the same as that shown in the firstembodiment.

The embodiment of FIGURE 8 is essentially similar to the embodiment ofFIGURE 1 except that here the pilot flame 106 emanates from opening 107at the top of an internal fuel passage 96. In this embodiment thepassage 96 is formed within the burner base 97 so that this base, whichmay be a casting or the like, may be fitted closely to the drip pan 108adjacent the pilot passage 96 in contradistinction to the embodiment ofFIG. 7. Otherwise, the operation is essentially the same as thatpreviously described with secondary air being provided through thecentral passage 98 to flow out the opening 99, primary air and gasmixture being provided from a passage 100 to flow out the main burneropening 101 and the flame relight ring burning being provided by flow ofprimary air-gas mixture from the passage 100 through openings (notshown) in a top wall 102 of burner base 97 to flow out the exit opening103.

In the embodiment of FIGURES 9-12 the burner assembly 109 comprises anintegral burner base 110 of generally annular shape that extends aboveand below the range top 10 and metal plate 56. The portion of the base110 beneath the plate 56 is provided with a radially extending tubularprojection 111 provided on its inner surface with a pair of annularinwardly extending projections 112. Extending into this tubularprojection 111 is a pipe 113 for supplying gas and primary air in themanner previously described in connection with the other embodiments.Located between the inner edges of the annular projections 112 and theouter surface of the pipe 113 is a compressed resilient sealing member114 such as a rubber seal so as to provide a fluid seal.

The bottom of the burner base 110 is closed by a .closure 115. The topof this closure 115 is sealed to the bottom of the base 110 by a gasket118. The closure 115 is provided with an upwardly extending tubular part116 located substantially concentrically of the burner base 110.Extending across the bottom of this tubular part 116 is the bottomclosure 117. Formed integrally with the bottom closure 117 is a radiallyextending pipe section 119 that functions to supply air in the mannerpreviously described. The tubular projection 111 and the annularprojections 112 previously mentioned are formed by cooperating halves atthe bottom of the burner base 110 and the bottom closure 115.

Positioned on the top of the burner base 110 is a preassembled unitaryburner head 120. This burner head or heat unit comprises an outercylindrical part 121 having an outwardly and upwardly extending flange122 and a concentric inner cylindrical part 123 having at its upper endan outwardly and upwardly extending flange 124. The lower flange 122 isprovided with upwardly extending spaced portions 125 which are attachedby a staked connection as indicated at 126 to the bottom of the upperflange 124. The spacing between these portions 125 provides for upwardlyand outwardly extending ports 127 functioning similarly to the exitports 23 of the embodiment of FIGURES 1-4.

Located within the burner head 120 integrally with and spaced inwardlyof the cylindrical part 123 is a spider 128 on which is mounted by meansof a rivet 129 a deflector plate 130. This deflector plate operates insubstantially the same manner as the previously described plate 35 ofthe embodiment of FIGURES 1-4.

Extending upwardly from the tubular part 116 is a central tube 131having its lower end received in the tubular part 116 and its upper endreceived in the cylindrical part 123. This tube 131 provides a passage132 for the secondary air from the pipe section 119.

The burner base 110 and the burner head 120 are held in assembledrelationship by the bottom of the cylindrical part 121 resting on aninwardly extending shelf 133 that extends inwardly of and is integralwith the cylindrical burner base 110. The cylindrical part 110 is spacedoutwardly of the cylindrical part 121 of the burner head 120 to providea passage 134. This passage 134 communicates through a plurality ofholes 135 with the internal chamber 136 that receives air and gasmixture through hte pipe 113. The upper edge of the burner base 110 issloped upwardly and outwardly and is spaced from the lower surface ofthe flange 122 in order to provide an exit port 137 that is similar toand functions substantially identically with the outlet 22 of theembodiment of FIGURES l-4.

The base of the bottom closure 115 of the burner assembly is providedwith spaced feet 138 resting on the burner box bottom 139. If desired,this burner unit may be suspended from the plate 56 by means of suitablefasteners connected between plate 56 and burner base 111).

In this embodiment, as in the embodiment of FIG- URES 1-4, the burnerassembly is sealed to the range top and to the plate 56 with a resilientseal member 140.

Formed integrally with the burner base 110 and extending outwardlytherefrom is a block 141 provided with a passage 142 the top of which isprovided with a pilot fitting 142a and the bottom of which is providedwith a fitting 143' for a gas line 144. This combination provides thegas supply for the pilot flame 145. This integral pilot structure alsopermits easier assemblage of the burner assembly and facilitates closercontrol of critical dimensional tolerances between the pilot burner andthe burner head 120. Adjacent the top of the pilot fitting 142a theupper portion of the burner base 110 is provided with an inner wall 146and an outer wall 147 spaced from each other to provide a chamber 148.This chamber 148 forms an initial ignition passage in which the gas isignited by the pilot flame 145 through an elongated vertical slit 149 inthe wall 147. Air and gas are provided in the initial ignition passage148 through an opening 150.

The burner assembly is provided with a depending hood or shield 151having an outwardly projecting portion 152 to enclose the pilot flame145. Within the hood 151 is a pilot burner shield 153, The hood 151rests on an outwardly extending shelf 154 on the burner base 110 and canbe removed from the burner assembly for cleaning purposes merely bylifting it upwardly from the 8 burner assembly without removal of anyother burner parts.

The embodiment of FIGURES 9-12 is of course a power burner with the airand fuel being supplied under pressure as described in the firstembodiment of the invention. In this instance, the grate will support apan, pot or similar utensil at the level indicated by the line 155 ofFIGURE 9. When it is desired to operate the burner as an atmosphericsecondary air burner itis only necessary to remove the bottom closure117 and the spider 128 and deflector plate 130. When this is done theresulting burner assembly will have the appearance of the embodiment ofFIGURE 13. Here secondary air flows upwardly at atmospheric pressurethrough the passage 132. In this instance, the top of the grate willsupport the pan, pot or other utensil at the level indicated by the line156 of FIGURE 9. This higher elevation permits additional air to besupplied at the .top of the burner. In this embodiment of FIGURE 13 adeflector disc 157 is attached to the top of the grate 158 in order toaid in deflecting this air outwardly. Suflicient air is provided for thesecondary air passage of the embodiment of FIGURE 13 by reason of thefeet or spacer lugs 138 permitting air to enter between the burnerassembly and the burner box bottom 139.

In addition to the outstanding operating characteristics of the burnerof this invention, it is important from the housewifes point of view torealize the important improvements in range top cleanability that thisburner provides over present gas range top burners. In the common rangetop application of the burner of this invention it is likely that aplurality of burners such as illustrated herein would be used. Theseburners would all be mounted on the same main body portion 12 and whenthe grates 66 and the hoods 63 were removed it can be seen that theentire range to-p area would be completely exposed for a thoroughcleaning. Since all members of the burners that protrude through themain body portion 12 are sealed, an ample amount of cleaning fluid canbe used without this cleaning fluid getting into the inner parts of therange.

Having described our invention as related to the embodiments shown inthe accompanying drawings, it is our intention that the invention be notlimited by any of the details of description, unless otherwisespecified, but rather be construed broadly within its spirit and scopeas set out in the accompanying claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A fluid fuel burner assembly comprising: a burner head defining amain passage, an auxiliary passage and a secondary air passage, saidburner head having a closed end, said passages each having an exitopening facing away from the longitudinal axis of the burner head andbeing located adjacent said end, the main passage exit opening beingdisposed between the auxiliary passage exit opening and said end, andthe secondary air passage exit opening being disposed between said mainpassage exit opening and said end; structure defining a free spacesurrounding the burner head outwardly of said exit openings and upwardlyopen to atmosphere; means for supplying combustible fuel-air mixture tosaid main and auxiliary passages to provide a main flame at said mainpassage exit opening and an auxiliary flame at said auxiliary passageopening; means for supplying secondary air under gauge pressure to saidsecondary air passage; and flow control means for causing the rate offlow of fuel-air mixture from said auxiliary passage exit opening to beless than the rate of flow of fuel-air mixture fro-m said main passageexit opening thereby to prevent extinguishment of said auxiliary flame,the secondary air being directed by said secondary air passage exitopening to maintain the fuel-air mixture passing from said main passageexit opening in igniting association with the auxiliary flame.

2. A fluid fuel burner assembly comprising: a burner head defining amain passage, an auxiliary passage, and a secondary air passage, saidburner head having a closed end, said passages each having an exitopening facing away from the longitudinal axis of the burner head andbeing located adjacent said end, the main passage exit opening beingdisposed between the auxiliary passage exit opening and said end, andthe secondary air passage exit opening being disposed between said mainpassage exit opening and said end; means for supplying combustiblefuel-air mixture to said main and auxiliary passages to provide a mainflame at said main passage exit opening and an auxiliary flame at saidauxiliary passage opening; means for supplying secondary air under gaugepressure to said secondary air passage; flow control means for causingthe rate of flow of fuel-air mixture from said auxiliary passage exitopening to be less than the rate of flow of fuel-air mixture from saidmain passage exit opening thereby to prevent extinguishement of saidauxiliary flame, the secondary air being directed by said secondary airpassage exit opening to maintain the fuel-air mixture passing from saidmain passage exit opening in igniting association with the auxiliaryflame, said burner head further having a pilot passage for fuel-airmixture provided with an exit opening communicating with the exterior ofthe burner head adjacent the main passage and auxiliary passage exitopenings; and means for providing a pilot flame adjacent said pilotpassage exit opening.

3. A fluid fuel burner assembly comprising: a burner head defining amain passage, an auxiliary passage, and a secondary air passage, saidburner head having a closed end, said passages each having an exitopening facing away from the longitudinal axis of the burner head andbeing located adjacent said end, the main passage exit opening beingdisposed between the auxiliary passage exit opening and said end, andthe secondary air passage exit opening being disposed between said mainpassage exit opening and said end; means for supplying combustiblefuel-air mixture to said main and auxiliary passages to provide a mainflame at said main passage exit opening and an auxiliary flame at saidauxiliary passage opening; means for supplying secondary air under gaugepressure to said secondary air passage; and flow control means forcausing the rate of flow of fuel-alr mixture from said auxiliary passageexit opening to be less than the rate of flow of fuel-air mixture fromsaid main passage exit opening thereby to prevent extinguishment of saidauxiliary flame, the secondary air being directed by said secondary airpassage exit opening to maintain the fuel-air mixture passing from saidmain passage exit opening in igniting association with the auxiliaryflame, said burner assembly further including structure defining a freespace surrounding the burner head outwardly of said exit openings andupwardly open to atmosphere and extending to below the level of saidauxiliary passage exit opening to provide atmospheric air from belowupwardly to the auxiliary flame.

References Cited by the Examiner UNITED STATES PATENTS 2,111,369 3/1938Marvin et al 12639 X 2,220,572 11/ 1940 Knupp 15899 2,298,307 10/ 1942Parker 126--39 2,467,626 4/1949 Norman 158-116 X 2,590,948 4/1952 Perow158-116 2,661,057 12/1953 Resek 158-1 10 X 2,664,153 12/1953 Swenson etal 1581 15 X 2,759,533 8/1956 Getz et a1 l58110 2,843,199 7/1958Brodbeck et a1 1581 16 2,870,829 1/ 1959 Williams. 2,960,157 11/1960Dolby 158-116 3,002,513 10/ 1961 Morasch 126299 FOREIGN PATENTS 78,15611/1894 Germany. 309,329 11/ 1955 Switzerland.

OTHER REFERENCES German printed application 1,032,196, printed June 19,1958 (2 pgs. spec, 1sht.dwg.).

FREDERICK L. MATTESON, JR., Primary Examiner.

PERCY L. "PATRICK, EDWARD J. MICHAEL,

Examiners.

H. B. RAMEY, D. C. BRUENING, Assistant Examiners.

3. A FLUID FUEL BURNER ASSEMBLY COMPRISING: A BURNER HEAD DEFINING AMAIN PASSAGE, AN AUXILIARY PASSAGE, AND A SECONDARY AIR PASSAGE, SAIDBURNER HEAD HAVING A CLOSED END, SAID PASSAGES EACH HAVING AN EXITOPENING FACING AWAY FROM THE LONGITUDINAL AXIS OF THE BURNER HEAD ANDBEING LOCATED ADJACENT SAID END, THE MAIN PASSAGE EXIT OPENING BEINGDISPOSED BETWEEN THE AUXILIARY PASSAGE EXIT OPENING AND SAID END, ANDTHE SECONDARY AIR PASSAGE EXIT OPENING BEING DISPOSED BETWEEN SID MAINPASSAGE EXIT OPENING AND SAID END; MEANS FOR SUPPLYING COMBUSTIBLEFUEL-AIR MIXTURE TO SAID MAIN AND AUXILIARY PASSAGES TO PROVIDE A MAINFLAME AT SAID MAIN PASSAGE EXIT OPENING AND AN AUXILIARY FLAMER AT SAIDAUXILIARY PASSAGE OPENING; MEANS FOR SUPPLYING SECONDARY AIR UNDER GAUGEPRESSURE TO SAID SECONDARY AIR PASSAGE; AND FLOW CONTROL MEANS FORCAUSING THE RATE OF FLOW OF FUEL-AIR MIXTURE FROM SAID AUXILIARY PASSAGEEXIT OPENING TO BE LESS THAN THE RATE OF FLOW OF FUEL-AIR MIXTURE FROMSAID MAIN PASSAGE EXIT OPENING THEREBY TO PREVENT EXTINGUISHMENT OF SAIDAUXILIARY FLAME, THE SECONDARY AIR BEING DIRECTED BY SAID SECONDARY AIRPASSAGE EXIT OPENING TO MAINTAIN THE FUEL-AIR MIXTURE PASSING FROM SAIDMAIN PASSAGE EXIT OPENING IN IGNITING ASSOCIATION WITH THE AUXILIARYFLAME, SAID BURNER ASSEMBLY FURTHER INCLUDING STRUCTURE DEFINING A FREESPACE SURROUNDING THE BURNER HEAD OUTWARDLY OF SAID EXIT OPENINGS ANDUPWARDLY OPEN TO ATMOSPHERE AND EXTENDING TO BELOW THE LEVEL OF SAIDAUXILIARY PASSAGE EXIT OPENING TO PROVIDE ATMOSPHERIC AIR FROM BELOWUPWARDLY TO THE AUXILIARY FLAME.